import type { Store } from 'express-rate-limit';
/**
 * A cross-replica rate-limit store under `rl:<namespace>:`, or `undefined` when
 * Redis isn't configured (express-rate-limit then uses its per-process memory
 * store, which is right for a single replica).
 *
 * Without a shared store every limit is really `max × replicas`, and weakest
 * exactly when an HPA has scaled out under load. Use a namespace unique to the
 * service AND limiter, so separate limiters never share a counter. Pair it with
 * `passOnStoreError: true`: a Redis outage then lets requests through instead of
 * failing them. A store whose scripts can't load at startup (Redis not yet
 * connected) is tolerated by express-rate-limit and reloads on first use.
 */
export declare function createSharedRateLimitStore(namespace: string): Store | undefined;
/** Test-only: forget the memoized client. */
export declare function __resetSharedRateLimitStoreForTests(): void;